First Attempt at Casting - Round Ball Undersized?

Tudenom

Tudenom

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Greetings wise ones.

I gave bullet casting a go this weekend with some success, but once I got my calipers out I was dismayed to find out my mould is throwing round ball undersized by upwards of 4 to 6 thou. It's a .454 diameter LEE double cavity mould. I can tolerate it casting ball down to 451 since this is for my cap and ball revolvers, but anything smaller is potentially a chain fire hazard.

Could casting temperature be a factor? I was able to get the lead up to about 610 degrees, but my propane camp stove couldn't get it any hotter. Does temperature have much effect on the casting size when casting pure lead?

If so, then I might go and find myself a bigger outdoor stove, might be useful if I start casting wheel weights.

Thanks for the help.
 
Temp has no effect in my experiances. Id check your calipers first off as far more cheap calipers out there, or users error. Not to say you dont know how to use them. But its alloy that shrinks more or less, usually pure lead shrinks more in comparison to lino type.
 
Try to beagle your mold. Calipers are often off, yes. Could you compare these bullets with some commercial ones in .451/.452?

How many bullets did you cast? The first handful might come out a bit small.

The real question is how do they fit your gun?
 
kg said:
Try to beagle your mold. Calipers are often off, yes. Could you compare these bullets with some commercial ones in .451/.452?

How many bullets did you cast? The first handful might come out a bit small.

The real question is how do they fit your gun?
Click to expand...

If they don't here are a couple of things to keep in mind...

Your mold should actually be made a bit over-sized to allow for shrink. (easy to do with round balls, not so easy with other shapes).

As stated above, if your molding temperature is too high, you will get more shrink.

Your mold also needs to be pre-heated; a cold mold will result in poor quality castings or shape distortions.

I used to cast bullets, and I would actually put the mold in the lead pot to heat up before starting. I no longer cast bullets, but as an engineer, look after injection molding processes where some of our dies weigh over 10,000 lbs; the exact same principals apply. (When they get that big, they have built in heaters). Molds that are too cold cause the material to "freeze off", resulting in undersized components often with missing features; molds that are too hot result in distortion, and in the case of plastic, burning or gassing.

When I did bullets, the first 3 or 4 castings went back in the pot.
 
Good suggestions guys.

I had a second look at the balls I cast, and it looks like the smallest of the bunch have wrinkles, so I'm guessing I'm having a hard time maintaining the mold temperature. My first kick at the cat had a lot of starts and stops, with lots of opportunities for the mold to cool off. Plus I'm casting at around 600 degrees, so there isn't much temp range and the mold might be cooling below the good casting temperature threshold.

Maybe once I start casting larger batches I'll have better luck maintaining my mold temp. I have a hot plate with a cast iron dish, so I could use that as a place to keep my mold hot while I'm loading more lead / fluxing / dicking around. I might as well invest in a smelting pot too instead of messing around with propane and cast iron pots.

I double checked my calipers against bullets with known diameters, including some .454 swaged balls and I'm getting good numbers. I'm fairly confident that my ball measurements are good. I did notice that my cast ball diameters aren't consistent, it seems to get wider the closer you get to the casting line, so beagling as kg suggested might be a good thing. I'll try loading a few balls of various sizes into my cylinders to check for fit and see if lead is being shaved off. If it's not then I'll beagle the mold with some aluminum tape and see what happens.
 
I think you got a good idea of the process, you need to get more familiar with your equipment now.

I didn't cast many RB's but it went very well with Range Lead and a bottom pour Pot (from LEE like the molds).

Standard bullets would cast very well with pure lead, once I figured out I needed a higher casting temp. I stopped using pure lead because it quickly oxydized, and my Ruger Old Army could handle other alloys.
There seems to be a difficult zone between 0 and 2 or 3 percents of tin for bullets to cast nicely. "Complex" molds with many grooves and bands are more sensitive.

There's one trick not mentionned so far (sorry if I missed it): I will smoke all molds' cavities regularly with matches, and leave the sooth in and between them. I feel that it helps consistency and cuts on wrinkles.
 
I find that pure lead comes out a tad smaller (drops easier) than ww lead ... so give ww lead a try. They may resist more when loading but that could still be a better option.
 
I float my molds on top of the molten lead until they are so hot that the lead drops off cleanly before I even think about casting the first bullet. The first couple or three are throw-aways without even looking; but usually everything is up to temp and filling out well after that.

Cold molds will give wrinkles and rounded edges where they are supposed to be square. The smallest of traces of oil will cause wrinkles too. Brake cleaner is your friend.
 
A quick Google check says that lead melts at 621 degrees F so if you're at 610 it will not even be completely liquid. WW melting temp varies according to the alloy mix but is considerably lower than lead (usually in the 500-550 degree F range). Wrinkled projectiles means your temperature is too low.

FYI from the Lyman Cast Bullet Handbook:
A table of predicted physical characteristics of bullets cast in various alloys.
44 cal.:
#429421 bullet
lead 256 gr;.4296 diameter
wheelweights 252 gr; .4303 diameter
Lyman #2 245 gr; .4310 diameter
linotype 238 gr; .4314 diameter

You can see that the lead shrinks the most.

Wheelweights will give you an increased diameter but will be harder which can mean difficulty loading them in a BP gun.
 
Tudenom said:
Greetings wise ones.

I gave bullet casting a go this weekend with some success, but once I got my calipers out I was dismayed to find out my mould is throwing round ball undersized by upwards of 4 to 6 thou. It's a .454 diameter LEE double cavity mould. I can tolerate it casting ball down to 451 since this is for my cap and ball revolvers, but anything smaller is potentially a chain fire hazard.

Could casting temperature be a factor? I was able to get the lead up to about 610 degrees, but my propane camp stove couldn't get it any hotter. Does temperature have much effect on the casting size when casting pure lead?

If so, then I might go and find myself a bigger outdoor stove, might be useful if I start casting wheel weights.

Thanks for the help.
Click to expand...

Quite often Lee molds throw undersize bullets or balls.

Depends on casting temperature and the alloy used. Pure lead and softer alloys shrink more than harder animony alloys. To produce a .454" ball with pure lead the mold cavity probably should be a few thousandths oversize. Normally this would be taken into account by the mold manufacturer, but it's common for Lee molds to be undersize.
 
Ted-Dent lists what happens with different alloys. Many (Many) years ago one of the mold companies advised that their advertised diameter was based on something like #2 (Lyman) alloy. Pure lead will cast a bullet with a smaller diameter, Lino-type larger.
 
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